Thin Solid Films, Vol.599, 78-83, 2016
Optimization of the post-deposition annealing process of high-mobility In2O3:H for photovoltaic applications
High-mobility hydrogen-doped indium oxide In2O3:H (IOH) were deposited by magnetron sputtering (radio frequency 13.56 MHz) from an In2O3 target in Ar/O-2/H2O gas mixtures onto unheated substrates. The as-deposited films were amorphous as shown by X-ray measurements and were crystallized in a post-annealing step in vacuum and air at 180 degrees C for 15 min. The optical, electrical, and morphological properties as well as the crystallization behavior of these transparent conductive oxides films were investigated in detail. A dependence of the annealing behavior in air on the total pressure during deposition could be shown. High carrier mobilities > 100 cm(2)/Vs allow for very low optical absorption and a low resistivity around 350 mu Omega cm. Amorphous IOH films were crystallized by short-term flash lamp annealing (FLA) in argon atmosphere for around 2.7 ms. Spatial temperature distributions in a typical layer stack (crystalline silicon, amorphous silicon, silicon oxide, and IOH film) were calculated within milliseconds after the FLA-treatment. Electron backscattering diffraction measurements of IOH films crystallized by FLA reveal a polycrystalline microstructure with an average lateral crystallite size of 333 nm. The crystallization process of these IOH films was studied by XRD and Hall measurements. (C) 2016 Elsevier B.V. All rights reserved.